Conveyor chains are a known conveying means, particularly in the field of the further processing of printed products, where they are typically used with grippers for conveying individual printed products. Using such conveyor chains with grippers, such as are described in the following patents of the same applicant: CH-644,816 (U.S. Pat. No. 4,381, 056), CH-592,562 (U.S. Pat. No. 3,955,667) or CH-588,647 U.S. Pat. No. 4,294,345), it is possible, if they are equipped with corresponding members movable against one another and guided in corresponding channels, to cover conveying paths in all directions (three degrees of freedom) and in particular with a large number of direction changes.
If the grippers are large, the units to be conveyed heavy and/or if for any reason the chain has to be positioned laterally or asymmetrically with respect to the units to be conveyed, the forces acting on the chain not in the conveying direction can become excessive. In such cases and as is described in Swiss patent application 1730/92-8 U.S. Pat. No. 5,188,349) of the same applicant, parallel to the chain path are provided rails or similar support means, on which are supported and guided e.g. by means of support rolls the said grippers. Such arrangements also make it possible to cover conveying paths having three degrees of freedom. They are suitable over relatively horizontal conveying paths, but offer no assistance in the case of very steep or even vertical conveying paths, so that they represent a restriction with respect to the conveying path configuration. In such cases, the grippers can also be positioned between two equidistantly positioned chains, but this restricts the conveying path configuration to two degrees of freedom, i.e. a restriction of the conveying path to a plane perpendicular to the surface in which the two chains run.